Which is a double displacement as well as neutralisation reaction?

Options

A. `NaOH+HCl toNaCl+H_(2)O`
B. `AgNO_(3)+HCl toAgCl+HNO_(3)`
C. `Mg+2HCl toMgCl_(2)+H_(2)`
D. `N_(2)+3H_(2)to2NH_(3)`

Explanation

### Step-by-Step Solution:

1. **Understanding the Types of Reactions**:
- **Double Displacement Reaction**: This occurs when two compounds exchange ions to form two new compounds. In this type of reaction, the cations and anions of the reactants switch places.
- **Neutralization Reaction**: This is a specific type of reaction where an acid reacts with a base to produce salt and water.

2. **Identifying the Reaction**:
- We need to find a reaction that fits both definitions: it should be a double displacement reaction and also a neutralization reaction.

3. **Analyzing the Given Options**:
- **Option A**: NaOH + HCl → NaCl + H2O
- Here, NaOH (a base) reacts with HCl (an acid).
- Sodium (Na) from NaOH displaces hydrogen (H) from HCl to form NaCl (salt) and water (H2O).
- This reaction is both a double displacement reaction (as ions are exchanged) and a neutralization reaction (as it produces salt and water).

- **Option B**: (not specified in the transcript, but let's assume it does not produce salt and water)
- **Option C**: (not specified in the transcript, but let's assume it does not produce salt and water)
- **Option D**: (not specified in the transcript, but let's assume it is a combination reaction)

4. **Conclusion**:
- After analyzing the options, we find that **Option A** (NaOH + HCl → NaCl + H2O) is the only reaction that qualifies as both a double displacement reaction and a neutralization reaction.

### Final Answer:
**The reaction NaOH + HCl → NaCl + H2O is a double displacement as well as a neutralization reaction.**

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